Changes of the winter North Atlantic Oscillation (NAO) variability in response to different climate forcings, and their possible causes, are decomposed and investigated using a set of atmosphere-only timeslice experiments forced by sea surface temperature (SST) from coupled runs. The results indicate that the effects of uniform SST warming and direct CO2 radiative forcing could enhance NAO vari...

[1] The North Atlantic Oscillation (NAO) is one of the most prominent patterns of atmospheric circulation variability over the Northern hemisphere, yet little is known about its underlying mechanism of phase conversion. Our analysis reveals that the recent decline of Aerosol Optical Depth (AOD) over the Subtropical Atlantic Ocean (SAO) contributes significantly to the enhancement of SAO Sea Sur...

Droughts in the Southern Great Plains (SGP) have been attributed to the cold phase of El Niño–Southern Oscillation or La Niña. While La Niña events have been clearly linked to winter droughts, their link to summer droughts has remained unclear. We analyze the difference in precipitation between dry and nondry summers over the SGP during La Niña years. Anomalously high geopotential height and su...

— Evidence is reviewed for climate change and its causes over the interval spanning roughly the past millennium. Particular emphasis is placed on patterns of climate change influencing Mediterranean climates of the Northern Hemisphere. The evidence is taken from studies using high-resolution climate “proxy” data sources, and climate modeling simulations. The available evidence suggests that for...

Freshwater ecosystems have been repeatedly shown to respond significantly to large-scale climatic fluctuations [e.g., Strub et al., 1985; Firth and Fisher, 1992; George and Taylor, 1995; Anderson et al., 1996; Schindler, 1997]. Because human demand for high-quality fresh water is continually increasing, the practical relevance of such responses for the large-scale management of inland waters is...

A flexible spatio-temporal model is implemented to analyse extreme extra-tropical cyclones objectively identified over the Atlantic and Europe in 6-hourly re-analyses from 1979–2009. Spatial variation in the extremal properties of the cyclones is captured using a 150 cell spatial regularisation, latitude as a covariate, and spatial random effects. The North Atlantic Oscillation (NAO) is also us...

The "North Atlantic Oscillation (NAO)" as defined in Walker and Bliss (1932) has been traditionally viewed as a teleconnection pattern with 'centers of action' in the Atlantic sector. In contrast, the "zonal index cycle", as articulated by Namias (1950), involves the interactions between a fundamentally zonally symmetric or 'annular’ mode and the eddies. The perceived dynamical significance of ...

This study has used TOMS AI as well as the reanalysis dataset of thirty-four years (1979-2012) to investigate the influence of atmospheric circulation on dust transport during the Harmattan period in West Africa, using Aerosol Index (AI) data, obtained from various satellite sensors. Changes in Inter-Tropical Discontinuity (ITD), Sea Surface Temperature (SST) over the Gulf of Guinea, and North ...

A nonlinear projection of the tropical Pacific sea surface temperature anomalies (SSTA) onto the Northern Hemisphere winter sea level pressure (SLP) anomalies by neural networks (NN) was performed to investigate the nonlinear association between ENSO and the Euro-Atlantic winter climate. While the linear impact of ENSO on the Euro-Atlantic winter SLP is weak, the NN projection reveals statistic...